MUMBAI U.S. private equity firm Blackstone Group LP (BX.N) and Indian developer Panchshil Realty are close to buying a majority stake in an office tower in Mumbai for about 9 billion rupees ($144 million), two sources with direct knowledge of the matter said.

The deal could be concluded as early as next week, said a source directly involved in the talks. Both the sources declined to be named as the details are not public yet.

Blackstone, ICICI Ventures and Indian Express Group declined to comment. Panchshil could not be reached immediately.

The Economic Times reported the deal earlier on Tuesday.

Blackstone has invested more than $500 million in buying leased property assets in India.

It is also in advanced talks to buy a business park in Mumbai for about 10 billion rupees and a special economic zone in Gurgaon for around 24 billion rupees, sources have told Reuters.

The 400,000 square-foot Express Towers overlooks the Arabian Sea and is home to several tenants including Blackstone, Bank of America Merrill Lynch (BAC.N), Temasek Holdings TEM.UL, Warburg Pincus and General Atlantic Company.